1. Field
At least one aspect generally relates to universal serial bus (USB) devices, and more particularly, but not exclusively, to triggering special modes of operation in USB-enabled devices.
2. Background
Universal Serial Bus (USB) is an industry standard that defines the cables, connectors, interfaces, and communications protocols used in a bus for connecting, communicating, and/or supplying power between electronic devices. Devices that implement USB include keyboards, pointing devices, digital cameras, printers, portable media players, disk drives, network adapters, smartphones, personal digital assistants, video game consoles, power chargers, among many other types of devices.
During early development stages of portable/embedded devices or in early boot stages of such devices, there is often a lack of keypad support which is desirable to trigger different modes of operation in the device. For example, such modes may include debug mode, logging mode, provisioning mode, or a combination of these modes, which may be used during development and/or testing stages of a device.
In one example, a provisioning process for embedded devices may be performed over USB. Existing methods to trigger such a provisioning mode include detecting an empty Flash or secure digital (SD)/embedded multimedia card (eMMC) card, or simply performing a USB enumeration and waiting for a command from a USB host. These methods are not useful or efficient in the cases where it is desired to force the device to enter provisioning mode or some other mode.
Therefore, there is a need for techniques that cause a device to enter a particular mode of operation without the use of a keypad.